Medicare covers most of the cost of outpatient surgery, but you pay a share through your deductible and coinsurance

Medicare Part B pays for outpatient surgery performed at a hospital or ambulatory surgery center. You are responsible for your Part B deductible (which resets each year) and then 20 percent of what Medicare approves as the cost. The surgeon's fee, the facility fee, and anesthesia are all covered under this same structure — Medicare pays 80 percent of each, and you pay 20 percent after you have met your deductible.

The actual amount you pay depends on what Medicare approves for your specific procedure in your geographic area. Medicare sets different approved amounts for the same surgery in different regions. If your surgeon charges more than Medicare's approved amount, you may owe the difference — unless your surgeon has agreed to accept Medicare's approved amount as full payment, which most do.

The total out-of-pocket cost is unpredictable without knowing your deductible status and your surgeon's billing practices. Before surgery, ask your surgeon's office for an estimate based on Medicare's approved amount for your zip code, and confirm whether they accept Medicare's approved amount as full payment.

Key Takeaways

  • Medicare Part B covers outpatient surgery at hospitals and ambulatory surgery centers, paying 80 percent of the approved cost after you meet your annual deductible.
  • You pay your Part B deductible first (the amount changes yearly), then 20 percent coinsurance for the surgeon, facility, and anesthesia combined.
  • The approved amount varies by region and procedure, so the same surgery costs you different amounts depending on where you live.
  • Ask your surgeon's office for a cost estimate before the procedure and confirm they accept Medicare's approved amount as full payment.
  • If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs may be lower because those plans cover some or all of your coinsurance.

How Medicare's payment splits between you and the program

Medicare Part B pays 80 percent of the approved cost for outpatient surgery. You pay the remaining 20 percent, but only after you have paid your annual Part B deductible. The deductible amount is set by Medicare each year and applies to all Part B services combined — once you have paid it, you do not pay it again that year.

The 20 percent coinsurance applies to the total approved cost, which includes the surgeon's fee, the facility charge, and anesthesia. If the approved amount for your procedure is $5,000, Medicare pays $4,000 and you owe $1,000 in coinsurance (after your deductible is met). This structure is the same whether you have surgery at a hospital outpatient department or at an ambulatory surgery center.

What "approved amount" means and why it matters

Medicare does not pay whatever a surgeon or facility charges. Instead, Medicare sets an approved amount — the maximum it will pay for a specific procedure in your geographic area. Your surgeon may charge more, the same, or less than this amount.

If your surgeon charges $6,000 but Medicare's approved amount is $5,000, Medicare pays 80 percent of $5,000 ($4,000). If your surgeon has signed a Medicare participation agreement, they accept $5,000 as full payment and you owe only your 20 percent coinsurance on the $5,000. If they have not signed the agreement, you may owe the $1,000 difference on top of your coinsurance — this is called balance billing.

Most surgeons and facilities accept Medicare's approved amount, but you should confirm this before scheduling. Call your surgeon's office and ask: "Do you accept Medicare's approved amount as full payment?" If the answer is no, ask what they charge and whether you can get that in writing.

How your deductible affects what you pay

Your Part B deductible is the amount you must pay out of your own pocket before Medicare starts paying its 80 percent share. Once you have paid the deductible in a calendar year, you do not pay it again until the next year begins. The deductible applies to all Part B services — office visits, imaging, lab work, and surgery all count toward the same deductible.

If you have already met your deductible earlier in the year (for example, through office visits or imaging), you pay only your 20 percent coinsurance for outpatient surgery. If you have not met it yet, you pay the remaining deductible amount first, then 20 percent coinsurance on the rest.

For example: if your deductible is $240 and you have not paid any of it yet, and your approved surgery cost is $5,000, you pay $240 toward the deductible, then 20 percent of the remaining $4,760 ($952), for a total of $1,192. If you had already paid the full deductible earlier in the year, you would pay only $1,000 (20 percent of $5,000).

Outpatient surgery at a hospital versus an ambulatory surgery center

Medicare covers outpatient surgery at both hospital outpatient departments and ambulatory surgery centers (ASCs). The payment structure is the same — you pay your deductible and 20 percent coinsurance — but the approved amount may differ between the two settings for the same procedure.

A hospital outpatient department typically has a higher approved amount than an ASC for the same surgery. This means your 20 percent coinsurance will be higher at a hospital. If your surgeon performs the procedure at both locations, ask which one Medicare approves at a lower cost and whether your surgeon can schedule you there.

Both settings must be Medicare-certified to bill Medicare. If you are unsure whether a facility is certified, ask your surgeon's office or search the Medicare Care Compare tool on Medicare.gov.

How Medigap and Medicare Advantage plans change your costs

If you have a Medigap (supplemental insurance) plan, it may pay some or all of your Part B deductible and coinsurance. The amount depends on which Medigap plan you have — some cover the full 20 percent coinsurance, others cover part of it. Check your Medigap plan documents or call your insurer to learn what they cover for outpatient surgery.

If you have a Medicare Advantage plan, you do not use Part B directly. Instead, your Advantage plan covers outpatient surgery through its own network. You typically pay a copay or coinsurance to the facility and surgeon, and the amount depends on your plan's design. Call your Advantage plan before surgery to learn your exact cost.

If you have neither Medigap nor Advantage coverage, you pay the full deductible and 20 percent coinsurance yourself. Some people choose to delay non-urgent surgery until early in the calendar year so they can spread the deductible cost across more services.

Getting a cost estimate before your surgery

Before you schedule outpatient surgery, ask your surgeon's office for a written cost estimate. Provide them with your Medicare information and ask them to look up Medicare's approved amount for your procedure in your zip code. They should be able to tell you the surgeon's approved amount, the facility's approved amount, and your estimated out-of-pocket cost based on your deductible status.

If you have already met your deductible for the year, the estimate should show only your 20 percent coinsurance. If you have not, it should show your remaining deductible plus 20 percent coinsurance on the approved amount above the deductible.

Ask the office to put the estimate in writing and to confirm that both the surgeon and facility accept Medicare's approved amount as full payment. This protects you from surprise bills after the procedure.

Frequently Asked Questions

Does Medicare cover all types of outpatient surgery?

Medicare Part B covers most medically necessary outpatient surgery. Cosmetic procedures and some elective surgeries are not covered. Your doctor can tell you whether Medicare covers your specific procedure. If you are unsure, ask your surgeon's office to verify coverage with Medicare before you schedule.

What happens if I have not met my deductible and the surgery costs less than the deductible amount?

You pay the full approved cost of the surgery, up to your remaining deductible. The remaining deductible carries over to the next calendar year. For example, if your deductible is $240 and you have not paid any of it, but your surgery costs only $150, you pay $150 and your deductible for next year will be $240 again (deductibles reset January 1).

Can I be balance billed for outpatient surgery?

Only if your surgeon or facility does not accept Medicare's approved amount as full payment. Most do accept it. Before surgery, confirm in writing that your surgeon and facility accept Medicare's approved amount. If they do not, ask for their full charge and decide whether to proceed or seek another provider.

Does Medicare cover anesthesia during outpatient surgery?

Yes. Anesthesia is included in the approved amount for outpatient surgery. You pay your deductible and 20 percent coinsurance on the total approved cost, which includes the anesthesiologist's or nurse anesthetist's fee. There is no separate charge for anesthesia.

What if my surgeon's office cannot give me a cost estimate?

Call Medicare directly at 1-800-MEDICARE and provide the procedure code (your surgeon's office can give you this). Medicare can tell you the approved amount in your area. Then calculate your cost: your remaining deductible plus 20 percent of the approved amount above the deductible.